Your knowledge is incorrect. Snaps don't have to be statically linked. They use a mount namespace with a predictable set of libraries that are maintained and receive security updates. In addition the application can bring additional libraries but those are on the application developer to maintain (or delegate to a hosted service like build.snapcraft.io to rebuild on security updates).
Sure, you can do static linking, you just don't have to and this is not how snaps work.
Sure, you can do static linking, you just don't have to and this is not how snaps work.